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Gewählte Doctoral Thesis:

Andreas Kreuzeder (2015): CHEMICAL IMAGING OF PHOSPHORUS DYNAMICS IN THE RHIZOSPHERE Development and Application of the Diffusive Gradients in Thin Films Method.
Doctoral Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 137. UB BOKU obvsg

Abstract:

Phosphorus (P) is one of the most limiting nutrients in modern agriculture. Soil P dynamics are mainly governed by pH, the concentrations of Fe, Al and Ca as well as the presence of competing organic and inorganic ligands. The investigation of these complex reactions and the occurrence of highly localized phenomena in the rhizosphere require novel methods and experimental approaches. Diffusive gradients in thin films (DGT) has been used as an analytical tool to study the solute distribution and dynamics in the rhizosphere. In this work a novel DGT resin gel was developed which is capable of binding anionic as well as cationic solutes and that is optimized for chemical imaging based on laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS). These methods were extensively validated and a new scheme for the calculation of uncertainty of DGT measurements was proposed. These novel methods were applied to investigate plant strategies for P uptake of Triticum aestivum L. cv. Carazinho, Fagopyrum esculentum Moench and Lupinus albus L. The results illustrate the different nutrient acquisition strategies which were reflected in the mobilization of nutrients in the rhizosphere. While buckwheat showed a very active root tip, wheat developed more homogeneous depletion zones along the root. Lupine plants developed cluster roots which were shown to be able to mobilize nutrients very efficiently. The parallel application of planar optodes (PO) to map pH distributions has further substantiated these different uptake mechanisms. While these developments offer new possibilities for the investigation of plant-rhizosphere interactions, further research is needed to develop a sound understanding of the complex P chemistry in soils and the approaches plants use to increase P uptake.

Betreuer: Wenzel Walter

1. Berater: Prohaska Thomas

2. Berater: Puschenreiter Markus